There is no need to include <linux/kernel.h> here, so remove it.

All files that include <linux/group_cpus.h> also already include
<linux/kernel.h>, so this can't break anything.

These files are:
$ git grep group_cpus\\.h
MAINTAINERS:F:  include/linux/group_cpus.h
block/blk-mq-cpumap.c:#include <linux/group_cpus.h>
drivers/virtio/virtio_vdpa.c:#include <linux/group_cpus.h>
kernel/irq/affinity.c:#include <linux/group_cpus.h>
lib/group_cpus.c:#include <linux/group_cpus.h>
---
 include/linux/group_cpus.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/group_cpus.h b/include/linux/group_cpus.h
index e42807ec61f6..ecc4708dc468 100644
--- a/include/linux/group_cpus.h
+++ b/include/linux/group_cpus.h
@@ -6,7 +6,7 @@
 
 #ifndef __LINUX_GROUP_CPUS_H
 #define __LINUX_GROUP_CPUS_H
-#include <linux/kernel.h>
+
 #include <linux/cpu.h>
 
 struct cpumask *group_cpus_evenly(unsigned int numgrps);
-- 
2.43.0